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Thread: TCC unlocks slips

  1. #1
    Senior Member
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    Aug 2007
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    Default TCC unlocks slips

    I've upped the TCC pressure to 1000 kpa and upped the slip ingagement 30% as well as setting max/min tcc duty solenoid to 100 % and 0%. I'm running 8 psi on an LS1 with 212 @ .050 camshaft and head work. I was sucessfully ramping on the dyno with the conveter locked when it started to jump in and out (perhaps just hot). How high have people pushed the stock converter in a 4L80E?

    Cheers

  2. #2
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    Default

    The changes seem to have fixed the problem, but how high can I go with TCC pressure?

  3. #3
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    Oct 2006
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    60

    Default Re:

    What engine/trans do you have? The stock TCC is designed primarily to improve gas mileage and not designed to hold under large amounts of torque; that's why the TCC unlocks under most conditions except cruising.

    Some folks in other forums have used the TCC to provide a slightly faster time in the quarter, but the stock TCC is not designed to be used under high load conditions.

    The TCC usually has one plate (some have three), but the friction surface is very small and can't take the torque. You may need to unlock the TCC at certain speeds and load conditions and let the Torque Converter slip.

    Older transmissions (TH350, TH400) didn't have lock-up Torque Converters and worked fine with reasonably large amounts of HP / Torque. You just need to add a trans cooler to dissipate the heat generated by the slipping.
    As a side note, on much higher torque older transmissions, folks used to remove the TC and add a "real" clutch in place of the Torque Converter; just used the clutch to get the great launch and prevent loss of power to the slipping TC.

    Fred
    Last edited by 97K15004WD; December 6th, 2007 at 12:58 PM.

  4. #4
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    Default

    No this is a 4l80e with full sized converter, I am mainly locking it for tuning to get to the low rpm, high load points that are hard to hit with a slipping converter. I have 8.9psi LS1 witha small cam an head mods, currently making 325 rwKw, but I believe there is a little more in it yet with timing. I don't plan to raise the boost as I've already maxed out trans pressures, I have a valve body mod that prevents an overpressure, apparently a problem withthe 4l80e.

  5. #5
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    Aug 2007
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    Default

    It holds Ok if I use the scan tool to lock it at the start of a power run but can't engage after the shift in normal driving, I've removed all WOT converter lock up.

    Joel

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